The present invention relates to a drilling and/or a percussion power tool.
A drilling and/or a percussion power tool is disclosed for example in the European patent document EP 0 429 475 A1. This power tool has a tool holder and an air cushion percussion mechanism arranged in a housing. The air cushion percussion mechanism has a guiding tube, in which a piston and a striker perform a reciprocating movement. An air cushion chamber is formed between the piston and the striker and then it is ventilated through at least one control opening in an outlet position of the percussion mechanism. The formation of an air cushion with the ventilated air cushion chamber is not possible, so that the percussion mechanism is turned off.
For releasing the percussion operation, the control opening is closeable by a control part arranged outside of the guiding tube. During pressing of a tool inserted in the tool holder against a treatment point, a displacement of the guiding tube is performed against a return force, until the control opening is closed by the control part. With the closed control opening, a pressure or suction, or so-called air cushion, can be formed in the air cushion chamber. The piston and the striker are axially reciprocatingly coupled through the air cushion.